| Experimental investigations are carried out to analyze variation regulations of parameters in flow field and their couple relations as explosion waves and flame propagating along tube or through multi-layer mesh construction and narrow parallel channels construction.Experimental apparatus used for explosion and explosion suppression of flammable gases in tube are set up. The constructions of explosion suppression are multi-layer mesh construction and narrow parallel channels construction.With premixed ethyne-air gases and propane-air gases, experimental investigations about explosion waves propagating and suppression in tube are dealt with. Experimental conditions are set as follows: Stoichiometric rate and atmospheric pressure are used for initial concentration of Ethyne(7.75%), propane(3.95%) and initial pressure; the inside diameter and length of tube, which is closed at ignition end and open at the other, are 81mm and 1.4~2.9m respectively; multi-layer mesh construction made of stainless steel, is vertical to tube axle, narrow parallel channels construction is parallel to tube axle.The new important concept, critical quenching value has been put forward. This concept can be used to denote energy loss of explosion wave transformed by mesh construction. The effects of multi-layer mesh construction on flame propagation in tube are analyzed. Empirical formulas about relationship between critical values, include of quenching speed, quenching pressure difference and quenching amount (the product of quenching speed and quenching pressure difference), and geometrical parameters, such as layer, screen mesh and wire diameter, are obtained. With the increase of geometrical parameter (n·M·d) , critical quenching pressure difference and critical quenching value increased, the higher the capability of quenching is. Suppression effects of multi-layer mesh construction on explosion pressure waves are introduced. A new way to design flame arrest has been put forward basing on flow of flame arrest design and study results of the experiment.An experimental study on the quenching of explosion for propane-air mixture when the flame passes narrow parallel channels is described. The relationship of flame velocity v, quenching diameter D and quenching length Lq has been given. The principle of quenching when the flame passes narrow parallel channels is discussed.These studies have positive effect on the development of explosion suppression theory and the application of explosion suppression technology. |
